JPH068678B2 - Flexible pipe - Google Patents

Description

Description: FIELD OF THE INVENTION This invention relates to a new flexible interlocking segmented drill well.

Conventional technology In order to drill a curved well hole, it is necessary to use a drilling pipe that can bend along a curve of deviation from the vertical. There are various proposals for forming a bent portion of a pipe without permanently deforming the pipe by using a conventional well pipe as a segment. For example, in U.S. Pat. No. 2,515,366, a plurality of generally circumferential slots are formed, each slot cutting through the wall of a tubular well and dividing the tube into a plurality of sections.

Since the slot is approximately circumferential, the slot engages each other away from the actual circumference and loosely interlocks to form a dovetail type tooth. The top and sides of each dovetail type are each relatively straight. Further, the dovetail cuts of this patent are aligned vertically with the following cuts in a straight line.

The straight sides of the dovetail type cuts of the above-mentioned patents allow for large strains when bending the well and can cause damage to the cuts when excessive force is applied to the bends. Sometimes,
When the drilling well pipe rotates under heavy load, the pipe may break at the stress concentration part. This is due to the fact that the slots are aligned vertically and the cut sides are straight.

The flexible drill well shown in U.S. Pat.No. 4328839 has a semicircular shape that crosses the sides of the interlocking teeth in opposite directions.
Improves the force-supporting effect between the teeth when the flexible well is bent. The construction of this patent has better characteristics than the previous patents. However, because there is no reliable stop between adjacent segments to prevent excessive axial strain, excessive elongation and damage can occur when axial loads are high. In addition, this arrangement creates a relatively narrow neck in the base of each interlocked tooth and can be damaged when subjected to excessive bending stress. That is, this configuration has the narrowest teeth and therefore the weakest locations at the maximum bending moment.

Other well-known documents about Sakuikan as a segment include US Pat. Nos. 2,382,933, 2515366, 2585207, 2682728,
There are 2694549, 3160218, 3903974 and 4067404.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention According to the present invention, there is provided a flexible drilling tube having a new interlocking tooth structure which solves the above-mentioned drawbacks.

A flexible tube according to the present invention comprises an elongate tubular member divided into a plurality of thick wall rigid tube segments, end-to-end contacting each of the intermediate segments. A plurality of interlocking teeth and complementary indentations at the ends, the teeth of one segment being interlocked within adjacent indents with sufficient clearance to form a limited relative motion joint between the segments; Each tooth has a curved crown portion, a tapered base portion and a generally flat shoulder between the crown and the base portion.

Action The flexible well tube of the present invention has high rotational strength and tensile strength.

The flexible drill well of the present invention has a large bending strength and maintains the integrity of the interlocking teeth.

The flexible drill well of the present invention has a secure lock that prevents excessive axial displacement between adjacent pipe segments.

The drilling tube of the present invention has an increased rotational strength due to the provision of offsets between successive incisions forming interlocking teeth.

The flexible drill well of the present invention has good support characteristics between adjacent segments, which reduces wear and prolongs the life of the drill well.

Examples and drawings for clarifying the features of the present invention will be described.

EXAMPLE The flexible drill well according to the invention is particularly useful for drilling laterally offset lateral holes. The interlocking tooth profile of the present invention, which will be described later, resists compressive, bending, and rotational stresses generated between drilling wells.

When excavating a hole that is displaced from the vertical direction to the lateral direction, the drilling well pipe must bend along the radius of the arc to enter the lateral hole, and return to a substantially straight shape in the next straight drilling well. During operation, the drill well string consists of a conventional drill well and a flexible drill well.

U.S. Pat. No. 4,343,369 shows a drill guide for use with the flexible tube of the present invention. In this patent the flexible well tube is referred to as the drive tube. In this patent, multiple drill wells are used to form part of the drill string and at least one flexible drill well is housed within the bore of the drill guide. A drill bit attached to the drilling well that ends in the drill guide cuts the hole. The drill guide guides the direction of the well and does not rotate with the flexible well tube of the present invention.

The flexible drill well 10 of the present invention shown in FIG. 1 is a long tubular member that is divided into a plurality of segments 14, 16, 18. The drilling well 10 is a rigid structure in a suitable example, and has a thickness that can withstand the compressive, bending, and rotational stresses generated between the drilling wells.

Segments 14, 16, and 18 represent the parts that represent the drilling well 10, and have devices 12 at both ends that connect to other drilling wells. The connection device 12 shown in FIG. 1 has a threaded pin end. A threaded box end is usually provided on the opposite side of the tube. Sakuikan
The opposite ends of ten threaded segments, eg pin end segments 14, connect to a plurality of intermediate segments, eg segment 16. Segment 16 represents all intermediate segments and is in end-to-end relationship.

A plurality of teeth 22 and complementary recesses 24 at both ends of the intermediate segment 16.
Have and. The teeth 22 of one segment 16 enter into the recesses 26 of the adjacent segment 18 and have an interlocking relationship with the teeth 27 of the segment 18 and have sufficient clearance to allow the segments 16, 18
It becomes a joint capable of relative movement in all directions between.

The width of the cut forming the teeth 22 and the depressions 24 is sufficient to allow the segments of the flexible well 10 to move relative to each other in the radial axial direction. If a torque is applied to the drilling well pipe 10 during the drilling well, the tooth flanks of one segment of the pipe will contact the recess flanks of the next axially adjacent segment, thus transmitting the torque to the entire length of the drilling well pipe. . During this time, the gap between the segments allows the entire tube to bend and accommodate relatively sharp bends in the well. The overall bend of the tube 10 is determined by the number of intermediate segments, the spacing between the teeth forming the segments. These parameters are varied to get the desired result of the tube designer.

In the preferred embodiment, the flexible well 10 is manufactured by cutting the walls of a conventional well to form the interlocking teeth of the flexible well to form the segments. Although other manufacturing methods can be used, the required product can be obtained by using a commercially available drill well as the starting tubular member. This results in sufficient wall thickness and the strength of the teeth can withstand the stresses used in the wells.

The present invention has a new structure for interlocking the segments 16 and 18 of the drill well 10. The teeth 22 and recesses 24 are formed by cutting out the wall thickness of the tube 10 to form complementary recesses with the teeth 34, 36, 38, 40 shown in FIG.

As shown in FIG. 3, each tooth 34, 36, 38, 40 has the same shape,
A semi-circular crown 42, two generally flat shoulders 44, 46 in the circumferential direction of the drill well and a taper extending axially downward and extending outwardly from the crown 42 of the tooth. Base 48
Have and. The diameter of the semi-circular crown 42 is approximately in the circumferential direction of the tube 10 and the arcs forming the semi-circle are approximately in the axial direction of the tube 10. The shoulders 44,46 form the remainder of the diameter with the top of the base 48 along the outer diameter ends forming the crown 42.

The tapered sides 50,52 of the base 48 form opposing approximately 90 ° arcs and the tapered sides 52,52 of the adjacent teeth 34,36.
Form a continuous semi-circular recess to engage the semi-circular crowns of the opposing teeth 38 of the next axially adjacent segment.
Therefore, if the segmented tube is compressed axially,
The crown of each semi-circular tooth engages the corresponding semi-circular recess of the next axially adjacent tube segment to form a ball and socket bearing surface to distribute the compressive force over a relatively large area. This shape significantly reduces tooth wear and maximizes the area of distribution of compression and sliding forces, since most of the work done in the drill well tube as a segment between drilling operations occurs under compression.

The configuration of the present invention eliminates the possibility of untimely elongation of the drill well 10 under tension. The elongation causes galling between the teeth of both segments or separation between the segments. When tension is applied to the drilling well 10, flat shoulders 44 and 46 opposite to the teeth 34 are formed.
Contacts the shoulder 56 of the tooth 38 and the shoulder 58 of the tooth 40, providing a secure stop and preventing further relative axial movement of the tube segments. The gap between the opposed shoulders limits the relative pivoting movement between the tube segments and limits the overall curvature during use of the tube 10. Therefore, the gap between the tooth and the recess is larger in the axial direction of the tube than in the circumferential direction of the tube, this gap being indicated as the gap G between the opposite tooth shoulders. The size of the gap G controls the amount of elongation of the segmented tube under tension as well as the relative rotational movement between the segments, which determines the overall curvature of the segmented well.

To avoid concentrating large forces on a small area, the tooth-to-recess clearance includes the dimensions of the clearance G so that the drilling well 10 does not contact each other at the maximum curvature expected to form during drilling operations. Specified in. Furthermore, almost all the compressive forces and torques that occur during the use of the drill well 10 are transferred to the smooth semi-circular facing surfaces of the tooth crowns of the circumferentially adjacent teeth of the axially adjacent segments and the complementary recesses. It is desirable to be supported along the way.

As shown in FIG. 3, the edge of the tooth is rounded at the joint between the shoulder and the crown, and the portion between the shoulder and the tapered base is also rounded so that a smooth bending action is achieved. It is desirable to prevent damage due to concentration of force.

The tooth configuration of the tube according to the present invention provides greater resistance to tooth damage. The bending moments that occur on the teeth when the tube segments bend relatively have a large circumferential component. Similarly, the torque transmitted through the drill tube to rotate the drill bit at the end of the tube string creates a circumferential force on each tooth of the tube segment. This force is shown as an arrow F in FIG. 3, and becomes large due to the extension of the moment arm M near the tooth base. However, in the configuration of the present invention, since the configuration of the base is tapered, the longer the moment arm, the greater the thickness of the tooth base, and therefore the tooth base has a greater structural strength than the crown portion. Known US patents
This is clear when compared with the configurations of 2515366 and 4328839.

When the open ends of FIG. 3 are joined, the formed tubular portion represents a generally circumferential interlocking connection between adjacent segments of the flexible well 10. In accordance with the preferred embodiment of the present invention, two teeth 3 are provided at each end of each segment of the flexible well.
4 and 36 and complementary recesses that separate the teeth 34 and 36 from each other. This two-tooth configuration provides ball-and-socket-type action with complementary semi-circular depressions between the teeth to provide maximum deformation during compression bending, maximizing tube strength and durability.

In order to further disperse the acting force in the segmented tube, two teeth formed at one end of the tube segment are offset in either direction from the complementary recesses at the opposite ends of the well segment. . In the preferred example, the teeth and recesses of each segment are counterclockwise about 12 ° octeted to each tube segment. This is shown in FIG.
Shown are ten segments connected to each other, the tooth and recess connections 28, 30, 32 offset counterclockwise from the previous connection.

The above description of the present invention is illustrative, and various modifications are possible with respect to the size and shape of the parts, materials and details, and the examples and drawings are not intended to limit the invention.

EFFECTS OF THE INVENTION The flexible well pipe of the present invention is effective for excavating a non-vertical hole.

The machining of interlocked teeth according to the present invention resists compression, bending stresses and torques produced between wells.

Furthermore, it has sufficient resistance to tensile loads.

[Brief description of drawings]

FIG. 1 is a perspective view of a part of a flexible drilling pipe which is a segment using interlocking teeth according to the present invention, and FIG. 2 is a drilling well of an embodiment in which notches forming complementary recesses with teeth are sequentially offset. FIG. 3 is a perspective view of a part of the pipe, and FIG. 3 is an enlarged development view of a part of the flexible drilling well pipe of the present invention having interlocking teeth of the pipe segment. 10: Flexible drilling well 12: Connection device 14, 16, 18: Segment 22, 27, 34, 36, 38, 40: Tooth 24, 26: Recess 42: Crown 44, 46, 56, 58: Shoulder 48: Base 50, 52: Side

Claims (16)

[Claims] 1. A thick-walled rigid tube having a plurality of segments (1
4, 16 and 18) and includes an elongated tubular member (10) in end-to-end relationship of the segment,
Each end of each intermediate segment (16) comprises a plurality of interengaging teeth (22,27; 34,36,38,40) and complementary recesses (24,26), the teeth of one segment Are arranged with sufficient clearance within the recesses of adjacent segments to form a joint that allows limited relative movement between the segments, each tooth having an arcuate crown portion (42) and a tapered base. A flexible tube comprising a portion (48) and a substantially flat shoulder (44, 46, 56, 58) between the crown portion and the base portion. 2. A flexible tube according to claim 1, wherein said bow-shaped crown portion (42) is substantially semicircular. 3. The flexible tube according to claim 1, wherein the flexible tube has two substantially flat shoulder portions between the crown portion and the base portion. 4. The flexible tube according to claim 1, wherein the tapered base portion (48) of each tooth has arcuate side portions (50, 52, 54) and is circumferentially arranged. A flexible tube characterized in that circumferentially adjacent arcuate sides (52, 54) of adjacent teeth form complementary recesses that receive corresponding teeth (38) of axially adjacent segments. 5. A flexible tube as claimed in claim 4 wherein the arcuate sides of each tooth form arcs of approximately 90 ° in opposite directions. 6. A thick wall rigid tube having a plurality of segments (1
4, 16 and 18) and includes an elongated tubular member (10) in end-to-end relationship of the segment,
Each end of each intermediate segment (16) comprises a plurality of interengaging teeth (22,27; 34,36,38,40) and complementary recesses (24,26), the teeth of one segment Are arranged with sufficient clearance in the recesses of adjacent segments to form a joint that allows limited relative movement between the segments, each tooth having a maximum circumferential dimension, A flexible tube having a portion where teeth are connected to the flexible tube. 7. The flexible tube according to claim 6, wherein the teeth include a curved crown portion (42) and a tapered base portion (48). 8. A flexible tube as claimed in claim 7 characterized in that the tapered base portion (48) of the tooth has opposite arcs (50, 52) on opposite sides. Flexible tube. 9. A flexible tube according to claim 8 wherein said crown is substantially semi-circular and the opposite arcs (50,52) forming opposite sides of said base are approximately 90 °.
A flexible tube characterized by including a circular arc. 10. A thick walled rigid tube is provided with a plurality of segments (1).
4, 16 and 18) and includes an elongated tubular member (10) in end-to-end relationship of the segment,
Each end of each intermediate segment (16) comprises a plurality of interengaging teeth (22,27; 34,36,38,40) and complementary recesses (24,26), the teeth of one segment Are arranged with sufficient clearance in the recesses of adjacent segments to form a joint that allows limited relative movement between the segments, each tooth comprising a semi-circular crown portion (42), The base of the semi-circle extends approximately in the circumferential direction of the rigid tube, the arc of the semi-circle extends approximately in the axial direction of the rigid tube, and the two shoulders (44, 4
6, 56, 58) are provided at opposite outer ends of the base of the semi-circle and are provided with a base portion (48) which is tapered substantially downward in the axial direction and outward in the circumferential direction. Flexible tube. 11. A flexible tube according to claim 10 wherein each end of said intermediate segment is provided with two teeth and two complementary recesses. Flexible tube. 12. A flexible tube as claimed in claim 10 in which the plurality of teeth formed at the ends of each segment are counterclockwise from the plurality of complementary recesses at the opposite ends of the segments. A flexible tube which is characterized in that it is offset to. 13. A flexible tube as set forth in claim 12 including two teeth and two complementary recesses at each end of said intermediate segment. 14. The flexible tube according to claim 10, wherein the gap between the tooth and the complementary recess is larger in the axial direction than in the circumferential direction. 15. A flexible tube as claimed in claim 10 wherein the adjacent edges of the tapered base of adjacent teeth on said one segment form a semi-circular depression. A flexible tube, characterized in that it receives a semicircular crown portion of corresponding teeth of a direction-adjacent segment. 16. The flexible tube according to claim 10, wherein each shoulder of each tooth of the one segment is engaged with a shoulder of each tooth of an axially adjacent segment. And a stop for preventing excessive displacement of the segments in the axial direction relative to each other.